"God, I feel like a woman!" Chan Marshall says, giggling and sounding absolutely nothing like country she-devil Shania Twain. "Can you believe how just a little bit of red nail polish can transform you?" she asks in her soft Southern accent in an aesthetically lit and perfumed treatment room at a San Francisco spa.

Although the latest shade of OPI nail polish (Matador Red, coincidentally the name of her record label) may give the winsome singer a new outlook on life, there are some things that are immutable. Like the shape of one's toes.

"A long second toe means you're extremely intelligent," Marshall says, wiggling her outsize one impishly. The manicurist nods her head in agreement.

"Yes, many say you are your feet," she says.

"Oh, I so agree," Marshall answers before bounding out of her chair in search of her Ugg boots.

Despite their simpatico moment, the manicurist races after her.

"You must not put those on," she admonishes. "You will ruin your pedicure."

"I'm sorry. Are you mad at me?" Marshall says with a lopsided grin, revealing a mouthful of perfect teeth.

The manicurist isn't, and merely pats Marshall's shoulder and tells her to be careful.

This spa employee is not the first to feel protective toward the beautiful woman- child known as Cat Power (though she has no particular affinity toward felines).

Marshall is a study in contradictions. The Georgia native is the embodiment of a steel magnolia, oozing broken vulnerability one moment and staring icily right through you the next. Known for her stultifying stage fright, which has routinely caused her to stop playing and chastise the audience for responding negatively to her songs, or stalk off stage, only to reluctantly return, after much coaxing, to finish her set.

Once, during a particularly grim live show in which Marshall's band left her standing alone onstage, the singer folded herself into the fetal position and refused to move. Audience members, fascinated by the odd spectacle, came up one by one to stroke her hair or massage her back.

"I really didn't mind that they did that," Marshall says, "because I felt like I was already dead -- that I wasn't even there anymore, or something."

Unbelievably, her visible discomfort when playing live hasn't alienated fans; it has endeared them to her. She is high priestess of the disaffected and wounded who identify with her bouts of melancholy, fear and reclusiveness. With her slow, strange, mournful songs of loss, love and fear, she speaks bravely for those who are not comfortable in their skins, making listeners feel as if they are eavesdropping on someone lost in a very private moment.

Her agitated stage presence has always been seen as an emblem of authenticity, in character with her painful and arduous pursuit of self-acceptance and understanding. Like Iggy Pop slashing himself with razor blades or Mike Patton defecating onstage, Cat Power is expected to do something unexpected, and audiences have been disappointed when she turns in a normal performance.

But that isn't the case anymore. In February, Marshall canceled her U.S. tour, citing unspecified health reasons, and checked into a rehab facility. Ostensibly to deal with a drinking problem that had escalated after a bad breakup four years ago, the stint provided the singer with much more than she bargained for.

"I've had the hardest time," she says. "For the past four years I was pretending I was fine by getting drunk every day. When I broke up with Daniel, my one true love, I started going downhill."

Well, has there ever been a better reason to self-medicate than a broken heart?

"Yeah, but for four years?" Marshall laughs sharply without amusement. "Enough was enough. That was like a light went on and I said to myself, 'Chan, you're not crazy.' I just snapped out of it. So people will say, 'Oh, so you're not drinking, so you're comfortable onstage.' But that's not it. I survived hell and got out of that place, only by realizing all of the wonderful things I have in my life -- the wonderful friends, the wonderful memories and the joy and luck and the fans -- that I never saw before."

Of a post-rehab show, she says, "I finally just understood that these people were there for me. I know it sounds silly, but I never knew that before. And now I feel like I have a responsibility to myself and my fans to stay happy and healthy. Of course, more to myself than them, but I feel, like, thankful and grateful for their support and belief in me when I was so messed up. Because I didn't know I was messed up."

The singer hasn't canceled or stopped a single show or displayed any aberrant behavior since rehab. Instead, she has been engaging crowds, teasing and flirting with fans, even making costume changes during shows. (She used to perform in oversize men's shirts, baggy jeans and raggedy hair.)

Perhaps the clearest indication of her mental state is that she's been eschewing her trademark eye-obscuring bangs.

"Yup, I sing now sometimes with my hair completely off my face," she says. "Isn't that crazy? I'll never not have bangs, but I can wear my hair completely off my face for the first time in my life. I'm totally, like, renewed, with a new lease on life."

It shows. Chanel head Karl Lagerfeld noticed and asked her to be the "Face of Chanel" representing the company's new jewelry line. As of this writing no contracts have been signed, but Marshall did attend a soiree thrown by the designer, and was bedecked in Chanel gems.

Marshall's looks and ethereal presence are from a bygone era, conjuring up images of British model Jean Shrimpton about the time Mick Jagger was dating her sister Chrissie, a less menacing Nico around the time of "Chelsea Girls" or Jane Birkin about the time she met Serge Gainsbourg. But despite her striking looks, it's Cat Power's songs that enchant listeners. Just ask Elton John, Beck, Dave Grohl, Eddie Vedder and the Flaming Lips' Wayne Coyne. All have either worked with her or expressed the desire to. Former Talking Head David Byrne commented on his Web site that her New York performance in June was "one of the best shows I've ever seen."

Her latest album, "The Greatest," released in January, earned her the best Billboard 200 chart position of her career, premiering at No. 34. None of her earlier albums has reached higher than No. 105.

Sitting in the nail salon, she hums a little snippet of something she's just written for a forthcoming album. Called "Oh Time," it's dark, mysterious, Southern.

"I guess you could say that. I was feeling pretty damn Southern when I wrote it," she says. "But I think I'm singing the same way now that I sang when I was 6 years old and my grandmother used to tape me. And I like the way that sounds a lot."

She also likes touring now (she plays two shows today at the Fillmore).

"The thing that's the most different in the way I approach a tour is that I don't dread it anymore," Marshall says. "The mood is set at sound check, when my backup singer or my bass player or somebody in the band starts humming a song like 'Can't Get Enough of Your Love,' and then the whole band just starts playing and then I start singing and I'm reminded, dude, this is fun."